how many boxes on an ekg is the R to R interval
3 to 5 boxes
how many boxes on an ekg is the QRS complex
< 3 boxes
< 0.12
PR interval on EKG is how many boxes
1 big box <.2 seconds
1 small box on ekg equals
.04 seconds
1 large box on ekg equals
.2 seconds
5 large boxes on ekg equals
1 seconds
causes of ST depression
ischemi
bundle branch block
tachy
ventricular hypertrophy
septal leads
v1, v2
anterior leads
v4 , v3
lateral leads
v5 , v6